Preparation method and application of ammonium ion pre-embedded Cu-MOF derived CuHCF / MXene electrode material

Abstract

This invention discloses a method for preparing and applying a CuHCF / MXene electrode material derived from ammonium ion pre-intercalation Cu-MOF, relating to the field of new energy nanomaterials technology. Using Cu-BTC as a sacrificial template, the material is synthesized under room temperature co-precipitation conditions via ammonium ion pre-intercalation and sheet-like MXene composite. The proposed preparation method is low-cost and simple, and the resulting electrode material exhibits excellent morphology and performance. When the prepared CuHCF / MXene composite electrode is applied to capacitive deionization, it demonstrates high NH4 content. + Adsorption capacity characteristics. This invention utilizes NH4... + The H atoms in CuHCF form hydrogen bonds with the N atoms in CuHCF, thus enabling them to bond with NH4+. + The adsorption potential energy is reduced, thereby improving the adsorption capacity. At the same time, its self-assembly with MXene improves the defects of CuHCF such as easy aggregation and poor conductivity.

Description

Technical Field

[0001] This invention relates to the field of new energy nanomaterials technology, specifically to a method for preparing and applying an ammonium ion pre-intercalated Cu-MOF derived CuHCF / MXene electrode material. Background Technology

[0002] With industrial development and population growth, large quantities of ammonia (NH4) are produced. + Wastewater discharge into cities causes eutrophication of water bodies and greenhouse gas emissions, potentially seriously harming the health of aquatic ecosystems. Effective removal of NH4 from wastewater is crucial. + This is a pressing problem that urgently needs to be solved. In recent years, capacitive deionization (CDI) wastewater treatment technology has attracted much attention due to its advantages such as low energy consumption, environmental friendliness, and regenerable electrode materials.

[0003] Capacitive deionization electrodes consist of electrode active materials, binders, conductive agents, and graphite current collectors, with the electrode active materials being the key factor determining the performance of capacitive deionization. Currently, carbon materials, metal oxides, and metal sulfides have been extensively reported as electrode materials in the field of capacitive deionization. Although the above electrode materials can be significantly improved in NH4 purification through structural design... + While CuHCF exhibits good performance, its intrinsic properties limit its ability to meet market application requirements. Prussian blue analogues (such as CuHCF), as typical intercalation materials, possess stable three-dimensional framework structures and large ion diffusion channels, while two-dimensional materials like MXene have large interlayer vacancies and high conductivity, making them suitable as host materials for rapid cation insertion / extraction in CDI. However, CuHCF prepared by traditional co-precipitation methods is mostly bulky and prone to agglomeration. This leads to NH4... + Defects such as difficulty in intercalation, ion diffusion, and slow reaction kinetics severely affect NH4 + Removal performance. Furthermore, due to the effects of van der Waals forces, MXene nanosheets tend to self-stack and generate irreversible aggregation, resulting in a severe reduction in exposed active sites and a deterioration of various excellent properties. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a method for preparing and applying an ammonium ion pre-intercalated Cu-MOF-derived CuHCF / MXene electrode material, using NH4 + The H atoms in CuHCF form hydrogen bonds with the N atoms in CuHCF, thus enabling them to bond with NH4+. + The adsorption potential energy is reduced, thereby improving the adsorption capacity. At the same time, its self-assembly with MXene improves the defects of CuHCF such as easy aggregation and poor conductivity.

[0005] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing an ammonium ion pre-intercalated Cu-MOF derived CuHCF / MXene electrode material is provided, comprising the following steps:

[0006] (1) Dissolve copper nitrate hexahydrate in deionized water to obtain solution A; dissolve pyromellitic acid in ethanol to obtain solution B; then add polyvinylpyrrolidone to solution B, then pour it into solution A under stirring conditions, transfer it to a high-pressure reactor, perform hydrothermal reaction, and obtain template Cu-BTC after centrifugation, washing and vacuum drying.

[0007] (2) The template Cu-BTC obtained in step (1) was added to an ethanol solution and sonicated to obtain solution C; potassium ferricyanide was added to deionized water to obtain solution D; then the flake MXene solution was added to solution D under stirring conditions and stirred; then solution C was added under stirring conditions and reacted; finally, ammonium chloride was added and stirred and reacted at room temperature; after washing and vacuum drying, CuHCF / MXene electrode material with ammonium ion pre-intercalation Cu-MOF was obtained.

[0008] Furthermore, in step (1), the molar mass ratio of copper nitrate hexahydrate, pyromellitic acid and polyvinylpyrrolidone is 2-5 mmol: 2-3 mmol: 0.1-0.3 g.

[0009] Furthermore, in step (1), the molar mass ratio of copper nitrate hexahydrate, trimesic acid, and polyvinylpyrrolidone is 3.6 mmol: 2 mmol: 0.1 g.

[0010] Furthermore, in step (1), in solution A, the molar volume ratio of copper nitrate hexahydrate to deionized water is 2-5 mmol: 15 mL; in solution B, the molar volume ratio of trimesic acid to ethanol is 2-3 mmol: 15 mL.

[0011] Furthermore, in step (1), the hydrothermal reaction is carried out at a temperature of 110-130℃ for 10 hours.

[0012] Further, in step (1), the ethanol is centrifuged and washed, and then vacuum dried at 60°C for 24 hours.

[0013] Furthermore, in step (1), copper nitrate hexahydrate can also be replaced with nickel nitrate hexahydrate.

[0014] Furthermore, in step (2), the molar mass ratio of template Cu-BTC, potassium ferricyanide, flake MXene and ammonium chloride is 60-90mg: 0.3-0.5mmol: 10-20mg: 60-80mg.

[0015] Furthermore, in step (2), in solution C, the mass-to-volume ratio of template Cu-BTC to ethanol solution is 60-90 mg: 15 mL; in solution D, the molar-to-volume ratio of potassium ferricyanide to deionized water is 0.3-0.5 mmol: 15 mL; and the concentration of the MXene flake solution is 5-8 mg / mL.

[0016] Furthermore, the concentration of the tablet-form MXene solution was 6 mg / mL.

[0017] Furthermore, in solution D, the molar volume ratio of potassium ferricyanide to deionized water is 0.3 mmol: 15 mL.

[0018] Furthermore, in step (2), solution C is added and reacted for 12 hours under stirring conditions at 20-25℃.

[0019] Furthermore, in step (2), ammonium chloride is added and stirred for 10 minutes, and then reacted at room temperature for 12 hours.

[0020] Furthermore, it was washed three times with ethanol and then vacuum dried at 60°C for 10 hours.

[0021] The present invention also provides the method for preparing the above-mentioned ammonium ion pre-intercalated Cu-MOF derived CuHCF / MXene electrode material, and the ammonium ion pre-intercalated Cu-MOF derived CuHCF / MXene electrode material obtained therefrom.

[0022] The present invention also provides the application of the above-mentioned ammonium ion pre-intercalated Cu-MOF derived CuHCF / MXene electrode material in capacitor deammonium ion removal.

[0023] The present invention has the following beneficial effects:

[0024] 1. The ammonium ion pre-intercalated CuHCF / MXene electrode prepared in this invention can improve its resistance to NH4+ by pre-intercalating CuHCF with ammonium ions. + The adsorption potential energy can also reduce NH4 + The diffusion potential energy of MXene is high. Simultaneously, the large interlayer spacing of MXene can hinder the aggregation of CuHCF particles and improve its poor conductivity. This composite structure is beneficial for improving the electrode material's resistance to NH4+. + Its effective adsorption capacity.

[0025] 2. The ammonium ion pre-intercalated CuHCF / MXene electrode prepared in this invention, when used as a cathode material in a CDI device, facilitates efficient NH4+ purification through reversible redox reactions and ion intercalation adsorption. + Resource recycling is a crucial aspect of electrode materials with significant commercial value. The ammonium ion pre-intercalated CuHCF / MXene electrode preparation method provided by this invention effectively overcomes the drawbacks of complex preparation processes and poor reproducibility.

[0026] 3. This invention allows control over the grain size of CuHCF derived from Cu-BTC, and because NH4... + The formation of hydrogen bonds between the H atoms in CuHCF and the N atoms in CuHCF is more conducive to obtaining excellent kinetic performance. The technical route designed in this invention for synthesizing ammonium ion pre-intercalation CuHCF / MXene complexes using Cu-BTC as a sacrificial template fully leverages the dual pseudocapacitance and synergistic reaction of CuHCF and MXene to jointly promote ion reaction kinetics, thereby enhancing its performance in CDI with NH4+. + Adsorption performance.

[0027] 4. This invention uses Cu-BTC as a sacrificial template, and synthesizes the electrode material under room temperature co-precipitation conditions through ammonium ion pre-intercalation and lamellar MXene composite. The preparation method proposed in this invention is low-cost and simple, and the obtained electrode material has excellent morphology and performance. When the prepared CuHCF / MXene composite electrode is applied to capacitive deionization, it exhibits high NH4 content. + Adsorption capacity characteristics. Attached Figure Description

[0028] Figure 1 The image shows the XRD pattern of the material obtained in Example 1.

[0029] Figure 2 SEM image of the material obtained in Example 1;

[0030] Figure 3 The constant current discharge curve of the material obtained in Example 1 is shown.

[0031] Figure 4 NH4 of the material obtained in Example 1 + Desalination capacity diagram. Detailed Implementation

[0032] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0033] Example 1

[0034] A CuHCF / MXene electrode material with ammonium ion pre-intercalation Cu-MOF derivative, the preparation method of which includes the following steps:

[0035] (1) Dissolve 3.6 mmol copper nitrate hexahydrate in 15 mL deionized water to obtain solution A; dissolve 2 mmol trimesic acid in 15 mL ethanol to obtain solution B; then add 0.1 g polyvinylpyrrolidone to solution B, and then pour it into solution A under stirring conditions. Transfer the solution to a high-pressure reactor and hydrothermally react at 120 °C for 10 h. After centrifugation and washing with ethanol, vacuum dry at 60 °C for 24 h to obtain template Cu-BTC.

[0036] (2) Add 60 mg of the template Cu-BTC obtained in step (1) to 15 mL of ethanol solution and sonicate for 90 min to obtain solution C; add 0.3 mmol of potassium ferricyanide to 15 mL of deionized water to obtain solution D; then slowly add 10 mg of 6 mg / mL flake MXene solution to solution D under stirring for 10 min, then slowly add solution C under stirring, react at 20 °C for 12 h, finally add 60 mg of ammonium chloride and stir for 10 min, then react at room temperature for 12 h, wash with ethanol 3 times, and vacuum dry at 60 °C for 10 h to obtain ammonium ion pre-intercalated Cu-MOF derived CuHCF / MXene electrode material.

[0037] Example 2

[0038] A CuHCF / MXene electrode material with ammonium ion pre-intercalation Cu-MOF derivative, the preparation method of which includes the following steps:

[0039] (1) Dissolve 3.6 mmol copper nitrate hexahydrate in 15 mL deionized water to obtain solution A; dissolve 2 mmol trimesic acid in 15 mL ethanol to obtain solution B; then add 0.1 g polyvinylpyrrolidone to solution B, and then pour it into solution A under stirring conditions. Transfer the solution to a high-pressure reactor and hydrothermally react at 120 °C for 10 h. After centrifugation and washing with ethanol, vacuum dry at 60 °C for 24 h to obtain template Cu-BTC.

[0040] (2) Add 90 mg of the template Cu-BTC obtained in step (1) to 15 mL of ethanol solution and sonicate for 90 min to obtain solution C; add 0.3 mmol of potassium ferricyanide to 15 mL of deionized water to obtain solution D; then slowly add 20 mg of 6 mg / mL flake MXene solution to solution D under stirring for 10 min, then slowly add solution C under stirring, react at 20 °C for 12 h, finally add 80 mg of ammonium chloride and stir for 10 min, then react at room temperature for 12 h, wash with ethanol 3 times, and vacuum dry at 60 °C for 10 h to obtain ammonium ion pre-intercalated Cu-MOF derived CuHCF / MXene electrode material.

[0041] Example 3

[0042] A NiHCF / MXene electrode material with ammonium ion pre-intercalation Ni-MOF derivative, the preparation method of which includes the following steps:

[0043] (1) Dissolve 3.6 mmol nickel nitrate hexahydrate in 15 mL deionized water to obtain solution A; dissolve 2 mmol trimesic acid in 15 mL ethanol to obtain solution B; then add 0.1 g polyvinylpyrrolidone to solution B, and then pour it into solution A under stirring conditions. Transfer the solution to a high-pressure reactor and perform hydrothermal reaction at 120 °C for 10 h. After centrifugation and washing with ethanol, vacuum dry at 60 °C for 24 h to obtain template Ni-BTC.

[0044] (2) Add 90 mg of the template Ni-BTC obtained in step (1) to 15 mL of ethanol solution and sonicate for 90 min to obtain solution C; add 0.5 mmol of potassium ferricyanide to 15 mL of deionized water to obtain solution D; then slowly add 20 mg of 6 mg / mL flake MXene solution to solution D under stirring for 10 min, then slowly add solution C under stirring, react at 20 °C for 12 h, finally add 80 mg of ammonium chloride and stir for 10 min, then react at room temperature for 12 h, wash with ethanol 3 times, and vacuum dry at 60 °C for 10 h to obtain ammonium ion pre-intercalated Ni-MOF derived NiHCF / MXene electrode material.

[0045] The physical properties of the material obtained in Example 1 were characterized using X-ray diffraction and scanning electron microscopy, and the results are shown in the figures below. Figure 1 and Figure 2 Electrochemical and capacitive deionization tests were performed on the material obtained in Example 1, and the results are shown in the figures below. Figure 3 and 4 .

[0046] Depend on Figure 1 It can be seen that, by comparing with the standard card, the material obtained in Example 1 can be determined to be a composite of CuHCF and MXene.

[0047] Depend on Figure 2 It is known that MXene exhibits a nanosheet structure, while CuHCF exhibits a particle structure. This composite structure is beneficial for the transport of electrolyte ions and interface electrons.

[0048] Depend on Figure 3 It can be seen that the specific capacitance is as high as 263.1 F / g at a current density of 0.2 A / g, indicating its good capacitive behavior.

[0049] Depend on Figure 4 It can be seen that NH4... + The adsorption capacity reaches a maximum of 38.9 mg / g, indicating that it has excellent electro-adsorption capacity.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing CuHCF / MXene electrode materials with ammonium ion pre-intercalation Cu-MOF derivative, characterized in that, Includes the following steps: (1) Dissolve copper nitrate hexahydrate in deionized water to obtain solution A; dissolve pyromellitic acid in ethanol to obtain solution B; then add polyvinylpyrrolidone to solution B, then pour it into solution A under stirring conditions, transfer it to a high-pressure reactor, perform hydrothermal reaction, and obtain template Cu-BTC after centrifugation, washing and vacuum drying. (2) The template Cu-BTC obtained in step (1) was added to an ethanol solution and sonicated to obtain solution C; potassium ferricyanide was added to deionized water to obtain solution D; then the sheet-like MXene solution was added to solution D under stirring conditions and stirred; then solution C was added under stirring conditions and reacted; finally, ammonium chloride was added and stirred for 10 min and reacted at room temperature for 12 h; after cleaning and vacuum drying, CuHCF / MXene electrode material with ammonium ion pre-intercalation Cu-MOF was obtained.

2. The method for preparing the CuHCF / MXene electrode material with ammonium ion pre-intercalation Cu-MOF derivative as described in claim 1, characterized in that, In step (1), the molar mass ratio of copper nitrate hexahydrate, pyromellitic acid and polyvinylpyrrolidone is 2-5 mmol: 2-3 mmol: 0.1-0.3 g.

3. The method for preparing the ammonium ion pre-intercalated Cu-MOF derived CuHCF / MXene electrode material as described in claim 1, characterized in that, In step (1), in solution A, the molar volume ratio of copper nitrate hexahydrate to deionized water is 2-5 mmol:15 mL; in solution B, the molar volume ratio of trimesic acid to ethanol is 2-3 mmol:15 mL.

4. The method for preparing the CuHCF / MXene electrode material with ammonium ion pre-intercalation Cu-MOF derivative as described in claim 1, characterized in that, In step (1), the hydrothermal reaction is carried out at a temperature of 110-130 °C for 10 h.

5. The method for preparing the CuHCF / MXene electrode material with ammonium ion pre-intercalation Cu-MOF derivative as described in claim 1, characterized in that, In step (2), the molar mass ratio of template Cu-BTC, potassium ferricyanide, flake MXene and ammonium chloride is 60-90 mg: 0.3-0.5 mmol: 10-20 mg: 60-80 mg.

6. The method for preparing the CuHCF / MXene electrode material with ammonium ion pre-intercalation Cu-MOF derivative as described in claim 1, characterized in that, In step (2), in solution C, the mass-to-volume ratio of template Cu-BTC to ethanol solution is 60-90 mg: 15 mL; in solution D, the molar-to-volume ratio of potassium ferricyanide to deionized water is 0.3-0.5 mmol: 15 mL; and the concentration of the MXene flake solution is 5-8 mg / mL.

7. The method for preparing the ammonium ion pre-intercalated Cu-MOF derived CuHCF / MXene electrode material as described in claim 1, characterized in that, In step (2), solution C is added and reacted for 12 h under stirring conditions at 20-25 ℃.

8. The ammonium ion pre-intercalated Cu-MOF derived CuHCF / MXene electrode material prepared by the method of any one of claims 1-7.

9. The application of the CuHCF / MXene electrode material with pre-intercalated ammonium ions as described in claim 8 in capacitor deammonium ion removal.

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